All-Optical Ion Beam Cooling and Online Diagnostics at Relativistic Energies

Recent experiments at the Experimental Storage Ring (ESR) at GSI have shown that relativistic Li-like C3+ ion beams can be cooled to an unprecedented momentum spread of dp=p ~ 10^-7 using a single-frequency laser tuned to the Doppler-shifted 2S1/2 -> 2P1/2 and 2S1/2 -> 2P3/2 atomic transitions. Although these results encourage the application of laser cooling to beams of other Li-like and Na-like ions at even higher energies as will be available at future storage rings at FAIR (Facility for Antiproton and Ion Research), two major concepts have to be demonstrated experimentally: First, efficient laser cooling of ion beams with large initial momentum spread, thus avoiding additional electron cooling to match the large momentum spread to the usually small momentum acceptance of the laser force. Second, all-optical measurements of the relevant beam parameters, thus overcoming the limited resolution of standard storage ring detectors such as the Schottky pickup electrode at ultra-low momentum spreads. The aim of this paper is to discuss the technical realization of these concepts as planned for an upcoming beam time at ESR.